Packed red blood cell (pRBC) transfusions save lives. However, hundreds of thousands of non-hemolytic transfusion reactions occur each year worldwide, ranging from mild fever and pruritis, to serious life- threatening reactions such as severe hyperkalemia, anaphylaxis, and transfusion-related acute lung injury (TRALI). Mild-moderate reactions drive patient discomfort, documentation, and testing costs while serious reactions can result in expensive intensive care, patient injury, and even death, driving increased healthcare utilization and cost. Currently, there is no easy solution to purify contaminants that cause these reactions from pRBCs. Therefore, CytoSorbents is developing HemoDefend-RBC?, an easy-to-use, in-line filter, that removes extracellular potassium (K+) plus a broad spectrum of other substances from pRBCs that may potentially harm transfusion recipients, including free hemoglobin, bioactive lipids, cytokines, reactive enzymes, and antibodies. These contaminants are either residual components from donor blood, or are generated during blood storage due to RBC deterioration and hemolysis. Hyperkalemia from excessive K+ is particularly a risk in patients requiring transfusion of large numbers of pRBC units due to trauma and high-risk surgery, those with renal insufficiency, as well as in pediatric patients. In the U.S., the only currently available means to address these contaminants is to wash units of blood. However, this takes considerable time, logistics and expense. HemoDefend-RBC is designed to filter pRBCs via gravity flow and requires no additional equipment or energy source. Filtration is compatible with current transfusion practices, including any of the standard anti-coagulants and additive solutions. The shelf-stable device is made of inert materials with no perishable or leachable biological components and can be readily gamma-sterilized. The HemoDefend-RBC filter leverages and extends CytoSorbents? proprietary adsorptive porous polymer bead technology platform for medical filtration. The initial focus of our U.S. regulatory strategy for HemoDefend-RBC will be the approval of a point-of-transfusion filter to remove extracellular K+ from pRBC units in order to reduce the risk of transfusion-associated hyperkalemia. Potassium can reach extremely high levels during cold storage due to the dysregulation of cell surface ion pumps and hemolysis that causes K+ to be released from red cells. The proposed Phase IIB bridge program provides funding, with matching funds from the company, for additional research, clinical development, and manufacturing scale-up activities, to drive U.S. and E.U. regulatory approval and international commercialization of HemoDefend-RBC. Availability of the HemoDefend-RBC filter will provide an easy-to-use, low cost solution to safely and effectively ?wash blood? of a broad range of contaminants without the expense, logistics, and time currently required to physically wash blood.